Fluid compressor



Patented .lune 14, 1927.

UNITED STATES PATENT oFFlcE.

BURTON S. A'IKMAN, 0F MILWAUKEE, WISCONSIN, ASSIGNOR T0 NATIONAL' BRAKE do ELECTRIC COMPANY, F MILWAUKEE, WISCONSIN, A. CORPORATION OF WIS- CONSIN.'

FLUID conrnnsson.

Application led September 5, 1925. Serial No. 54,632.

My invention relates to fluid compressors and the `general object is to provlde 1mproved construction and arrangement for cooling and preventing overheating of the 5 discharge 'end My inventionv is particularly applicable to the type ot compressors d isclosed in my co-pending application, Serlal No. 737,725, filed September 15, 1924, in

which I have shown ai sleeve valve operated by ring friction andspeciiically an elastic,

yieldable and non-'metallic seat inserted in the cylinder head for noiseless sealing cngagement with the upper end of the sleeve or liner intake valve, but it is not intended to limit the present invention Vto such specific embodiment. The discharge valve construction of my invention is ot' great value regardless ot' the character of the intake valve construction.

The heat caused by the compression of the fluid has its greatest edect upon the compressor at the discharge end ot the c linder and in the discharge passageway. e surrounding material soon becomes heated and the heat of the head and upper end oi the cylinder tends to build up the temperature to a point where cylinder lubrication tails and the compressor can no longer operate.

In the case of a compressor using the sleeve' valve with a yielding seat, the temperature must be limited to prevent destruction ot the material torxning` the seat. The heated compressed air is driven from the discharge passageway past the discharge valve and into a valve chamber, and unless suitable provision is made for prevention, the heat in the walls vof the valve chamber will bc conducted to A the cylinder head and from thence to the intake valve seat and to the cylinder walls.

to Inprior structures the valve chamber has been formed directly on or in the cylinder` head in order tobring the discharge valve scat as closely as possible to the lupper'end of the cylinder tor minimum clearance and to insure maximum volumetric efficiency. Previous constructions have disposed the discharge valve pockets on or in the head with resultant overheating ot the head by the hot compressed nir. At the same time the temperature ot the cylinder wall rises and unless provision is made for conducting away the heat, as by Water cooling, continuous .operation is impossible. l

In accordancewith m present invention, I place the discharge va ve chamber and the discharge valve seata considerable distance from the cylinder head and between the chamber and the head I provide means which will reduce to a minimum the con- I duction of heat to the head. The juncture between the valve chamber bodyand the cylinder, head is of material which is a poor conductor oi\heat. A practical arrangement is to 'make the cylinder head and valve chamber integral and of such metal as cast iron, 'which haslow, heat con'dlilctivity, and

with such arrangement I.V make the walls I also provide a dischargevpassageway of` amplevolume, and in order to limit the clearance yand to insure maximum discharge ot' compressed duid from the cylinder, I providejan extension onthe end of the compressor piston alor iitting into said passageway when the piston is at the end oi its compression stroke, and such extension will then act as a suction plunger in the passageway so that when the piston starts to recede, cool intake Huid will be sucked through the space between the extension sides and the assage way and into the increasing space etween the extension end and the closed discharge valve, as the piston recedes, so that the walls around the discharge assageway will be cooled immediately at t e beginning oi the piston intake stroke and localization and accumulation of heat at the discharge end will thus be prevented. 'Ihe cylinder extension engaging in. the discharge passageway will also be cooled at the beginning of the' recession stroke 'ot the piston. By the foregoing arrangement I am able to secure continuousl output from an air cooled coin-` -pressor running at relatively Vhigh speeds and at high eiciencies, even in small sizes. While the invention'is particularly applicable to compressors of small size air cooled it ldd thermal contact and any excessive tempera.

ture of the head tends to reach the cylinder frame and be thrown off by the cooling fires 40. The head mayv also be provided with cooling tires if deslred.

I Briey describing the operat1on, whilejthe iston is traveling downwardly, fresh fluid ows into the cylinder through the intake passageway 18 and the gap 20 between the liner 6 and the seat 13 in the cylinder head, a stream of cool fluid being thus swept across the seat 13 and, in fact, across the .entire bottom ofthe cylinder head. As soon as the piston starts to travel upwardly, the liner 6 will be moved and held by ring friction against the seat 13 -to shut 0H the supply luid and the Huid within the cylinder will be compressed and discharged past .the check valve 21 into the valve lchamber' 22 and into the line 27. Entry of the dome 29 into the discharge passageway 28 assures substantially complete discharge of compressed fiuid. As described, the thin wall sections 30, 31 and 32 resist the conduction of heat from the valve chamber housing to the seat material. 13. At the end of the compression,I stroke the piston stops and reverses its motion.' The rings seize the liner 6 and instantly open the gap 14, letting out immediately or venting the gas compressed into the clearance space and taking it away fromfcontact with the head,

. liner and piston. The dome 29,V during the recession of the piston, acts as a suction plunger in the passageway 28I for, as soon as the discharge valve 21 is closed and the materia ,i passes through the gap 2O during recession of the piston starts to move downwardly and reo ens the intake gap 20, the pressure above.

t e end of the dome in the passagewa 28 will be reduced below the pressure o the incoming fresh iuid and the coo'l fluid will thus be drawn rapidly into the space behind the dome, this cool fluid passing between the sides of the dome and the -adjacent walls and extracting heat which such walls have taken on from the valve housing 23. The accumu lation of heat in the walls around the discharge lpassageway and above the .seating 13 is thus prevented. As the dome iston, the cool incoming fluid will strike t e dome sides and will reduce the temperature thereof. .The heat resulting from compression is thus prevented from localizing and accumulating; the 4liner'abutment-or seat 13y -is thus full protected against overheating and its ife `greatly increased.` i v In Fig. 2`I have shown an" embodiment in which the valve ocket 23 is physically separated from the ead 10 bya hollow block 35 of insulating ,material which may bemica,

"lava, porcelain, or the like, clamped between `the bottom of the valve pocket 23 and the top of cylinder head 10' by. means of the A liange 36 and bolts 37. The mode of operation and use is the same as that disclosed and described in connection with Fig. 1.

In Fig. 3 I have 'shown a modiiication part secured to the outer periphery of the head or clam 'by means of la fiance under the bolt 12. ikewise, a shield or ange 43 is connected to the bottom of the frame 23 of the Valve ocket 22 in such manner as to keep the cooling water out of contact with the walls of the pocket 22, but to permit the water in the hopper to come in free contact with the upper surface of the head 4l andI with the neck or connection 30 through which the discharge passageway 15. is formed.

It is highly desirable to keep the water out of contact with the walls of the exhaust valve pocket 22 for the reason that the water will be unnecessarily heated by the heat of the discharge compressed gas, whereas all that is desired is to -cool the neck 30 and the head 41.` No advantage is secured in pocket 22, so far as cooling the head is concerned. It is desirable to conduct as little heat as possible to the iange or cup 4:3, although I have in the illustration shown this cup' or fiange as made integral with the bottom of the chamber 23.

It is further to be understood that instead of an open hopper a closed water jacket ovea` the head and around the neck 30'may be provided. I ind, however, that with the ar rangement shown in Fig. 3 continuous'operation of a relativell large sized compressor may be carrie on for a long time with a charge of water contained in the hopper 42. VThe water does two things, first it gives a much greater radiating surface in conjunction with the hopper 42, and next it may, by evaporation, vcarry oii' a great amount of heat 4without permitting the telnperature to rise abovethe boiling point.

The construction shown is not to be limited to compressors asl it is` adaptable to internal .combustion engines and the like.

I do not intend to be limited to the details shown or described.

Having describedv my invention, Irclaim as follows 1. In combination, a cylinder head, a closed discharge valve chamber spaced from said head for retaining. rhot compressed air,

A under pressure, a connection between Said chamber and head of low heat conductivity to liniit the travel of heat from said compressed air to said liead, there being a passageway through said head and connection, a valve in said chamber controlling said passageway, and an intake valve having a seat-l supported by said head independently of said passageway.

2. ln combination, a cylinder head, ahousing lorniing a valve chamber, said head and housing being castr integral of a metal of low heat conductivity, a passageway through said head leading to said chamber, a valvein said chamber controlling said passageway, said housing being spaced a distance away lroiu said head and the metal between said housing and said head being of reduced cross' sectional area in order to retard the conduction ot heat therethrough and a rela- 'iivcly stationary intake valve below the head. v

il. ln combination, a cylinder havinga cylinder head, a housing forming a valve chamber, a passageway from said cylinder to said chamber, a valve in said chamber controlling said passageway, said housing being spaced from said head, and a wall connecting said housing and head, said wall being el poor heat lconductive material and of re-l duced cross` section in order torctard conduction of heat therethrough and a separate intake passageway under `the head and arelatively stationary valve therefor.

O-l.v In combination, a cylinder having a fluid inlet, -an iinperforate piston reciprocable in said cylinder, a head 'for said cylinder, a housing 'forming a valve chamber connected with said head, said housing being Vdisplaced a distance away from said head, a

discharge passageway through said head and housing, a 'discharge valve in .said chamber,

and an extension 'on said piston for engaging in said passageway during discharge stroke of the pisto 5. In combination, a cylinder having a fluid inlet, a piston in said cylinder, a head for said cylinder, a relatively stationary inlet valve below the head, a housing forming a valve chamber cro-axial with saidcylinder, said housing being spaced a distanceaway from said head and supported thereon, an extended passageway through said head and housing for connecting said cylinder with said chamber, a discharge valve seatedin said chamber, and a plungerl extension on said piston for enfraging in said passageway during the discharge stroke of the piston for expelling the fluid from said passageway into said chamber.

lcis

6. In a compressor, thecombination of a cylinder'having .a Huid inlet, a piston for said cylinder, a. housing Aforming a valve chamber, walls forming a passageway be- 4an elongated neck supporting said frame on therethrough, a discharge valve in said 70 chamber controlling said passageway, said passageway being out of thermal contact with the iiuid drawn through the fluid inlet, and a plunger extension on said piston for littingl into said passageway to discharge the compressed iuid therefrom during the compression stroke of the piston.

7. In combination, a cylinder havin a head, a frame forming a valve cham er,

S0 said head, a 'passageway through said head and neck into said valve chamber, a valve in said valve chamber controlling said passageway, said neck being of material resistant to vheat conduction` said cylinder having a separate intake passageway out of thermal cont-act with the discharge passagewav.

8. In combination, a cylinder, a structure forming a head for said cylinder and a valve chamber` a passageway through said structure connecting said cylinder and chamber', a valve in said chamber controlling said passageway, the structure between said chamber and head being contracted to provide insulating space between said chamber and head and an elongated neck of reduced cross sectional arca for resisting the conduction'v yoi* heat between said chamber and head, said cylinderhaving a separate intake passageway out of thermal contact withfthe discharge passageway.

9. In combination, a cylinder having a movable liner, a head for the cylinder, a.' seat of yieldable material supported on the inner side of said head in position to vbe engaged by the upper end of said liner durin upstroke of the piston, a housing above said head forming a valve chamber, a passageway through said head and housing to said chamber, al valve in said chamber con- Y trolling said passageway, the Amaterial between said seat material and said chamber being of reduced cross section for resisting the conduction of heat from said chamber to said material. t

10. In a compressor, the combination of a cylinder, a. movable liner therefor, a head for the cylinder, a seat of yielding material supported on the inner sideof said head to be engaged'by said liner during compression stroke of said piston, a housing form- 11. In a pressure fluid device, a cylinder having a head, a gas discharge passage leading lthrough the head, a valve for said passage, and a neck of relatively low heat conductivity separating said valve from said head and defining said passage, said cylinder having a separate intake passageway out of thermal Contact with said discharge pas-A sageway.

12. In a pressure fluid device, a cylinder having a head, a gas discharge passage leading through the head, avalve for said passage, a neck of relatively low heat conductivity separating said valve from said head and defining said passage, and a water jacket or said head and neck out of thermal contact with the compressed gas beyond the valve.

13. In combination, a cylinder head, a discharge valve chamber spaced from said head, a connection between said chamber and head of low heat conductivity, there being a passageway through said head and connection,

a valve 1n said chamber controlling said passageway, and cooling means for cooling:

said head and connection, said means being out of. thermal Contact with the discharge valve chamber.

1.4,. In combination, a compressor having a cylinder, a head for the cylinder, a discharge valve chamber mounted on said head but separated therefrom by a neckof low heat conductivity, a discharge passageway extending through the neck and to said dis-- charge valve chamber, ak discharge valve controlling said passageway, and' an inlet discharge valve valve disposed below the head, said valve having a seat on said head.

15. In combination, a com ressor, a cylinder therefor, a head for t e cylinder, a chamber mounted on said head but separated therefrom by' a neckot low heat conductivity,a valve in said chamber, and an annular inlet valve disposed below the head at the upper end of the cylinder and providin a narrow opening of relatively great lengt into the upper end of the Cylinder.

'16. Inpan air compressor having a cylinder and a piston, the method of limiting the temperaturevrise of the cylinder head -which path which is substantially free of thermal Contact with the air under compression.

17. In a compressor, a cylinder having a head, a discharge valve chamber spaced from the head and adapted' to retain air under pressure, a piston for said cylinder, crank means for reciprocating said piston in said cylinder, said piston and cylinder'having a relatively small clearance to provide a relatively high compression ratio, said chamber having va discharge check valve. and being connected to the cylinder by a hollow connection of low heat conductivity, and an air intake passageway independent of said discharge connection. y

18. In a power drivencompressor of the type adapted for continuous compression of a gas and in which heating of the head'becomes a limiting actor, the combination of a cylinder and piston, a head for the cylinder, a discharge valve chamber spaced from the head and communicating with a closed reservoir, a valve for said chamber, a hollow connection of low heat conductivity leading from the cylinder to said chamber, said compressor havingan intake passageway out of heat conducting relation with the discharge passageway.

19. In combination, a cylinder head, a discharge valve chamber spaced from said headl and adapted to retain heated gases under pressure, a connection between said chamber and head of low heat conductivity, there being av passageway through said head and connection, a valve in said chamber controlling said passageway, and a yielding intake valve seat mounted on the bottom of the head. l

In Witness whereof, I hereunto subscribe my name this 31st day of August, 1925.

` BURTON s. AIKMAN. 

